Hot Topics:

Idylwilde Dam site gets new life

The Idylwilde Dam was demolished after being damaged in the September flood

By Jessica Maher

Reporter-Herald Staff Writer

Posted:
05/04/2014 05:13:42 PM MDT

Justin Anderson, a hydrologist with the U.S. Forest Service, walks next to an excavator moving material by the Big Thompson River on April 3, where restoration work was being done in the vicinity of the former Idylwilde Dam site. (Steve Stoner / Loveland Reporter-Herald)

These days when driving through the Big Thompson Canyon, even the most astute traveler can barely make out the spot where a 238-foot long dam sat for nearly a century.

And that's exactly the point.

A major project on the site of the former Idylwilde Dam has brought local, state and federal agencies together over the past seven months, after the flood made such collaboration necessary.

With dam destroyed and then demolished, the goal is now to restore the area and determine its best future use. That's likely to include fishing access, though in a stream setting now instead of a reservoir.

"It's been a great working partnership for everybody involved, all wanting to do what's right for the environment and what's right for the people living in the canyon," Loveland Water and Power Director Steve Adams said.

From Dam to Road

Built in 1917, the Idylwilde Dam went online in 1925 with a hydroelectric plant located at Viestenz-Smith Mountain Park to allow generation and distribution of electricity to the growing city of Loveland. Producing about 900 kW, it came to represent only a fraction of Loveland Water and Power's needs and in recent years was used to help reduce the city's costs during peak demands.

The dam was rebuilt after the 1976 flood, but the damage in the 2013 flood was devastating.

Last October, the City Council approved entering a contract with Kiewit Corp. to demolish the Idylwilde Dam. The contract allowed Kiewit, the contractor selected by the Colorado Department of Transportation for the U.S. 34 reconstruction project, to remove the debris that accumulated behind the dam during the flood for highway reconstruction.

Advertisement

It turned out to be a goldmine. According to senior water resources engineer Larry Howard, the project provided about 114,000 cubic yards of material for U.S. 34 reconstruction including all the sediment that had built up behind it and the structure itself.

Another 19,000 cubic yards of sediment was used by Larimer County to rebuild roads downstream and about 14,000 more will be headed to the Glen Haven area to help with reconstruction of private roads.

Pre-Dam Condition

Flood damage in September destroyed the Idylwilde Dam west of Loveland, seen in this aerial photo taken after the flood. The dam was demolished last fall, leading to a restoration effort in the area. (Jeff Swanty / Special to the Reporter-Herald)

With the dam gone — and that means everything removed down to bedrock — the city went to work planning for what's next. Loveland has an easement for the dam, reservoir and sections of pipeline that are on U.S. Forest Service property, making it the city's responsibility to restore the area.

The site had been on the Forest Service's radar even before the flood, but the demolition required a full-picture approach to the future, according to Reghan Cloudman, spokeswoman for the Canyon Lakes Ranger District of the U.S. Forest Service.

"We have to have some kind of conclusion to it, while making sure we're doing the best that we can for the environment and our resources that we have up there," Cloudman said.

Boulder-based Walsh Environmental is the city's consultant that was hired to figure out how the area — about a 600-foot stretch from behind the former dam to in front of it — looked before the dam was built.

"The idea is for the river to be how it was pre-dam or where it makes the most sense now," Cloudman said.

Without photographs or anecdotes to rely on, crews had to dig to find the natural channel.

"It's a unique opportunity that you have to restore a river where a reservoir was," Adams said.

Making a River

To help restore the population of fish and other wildlife, crews have planted trees in the riverbed, created an island and pulled in boulders to create the pools and riffles one would expect to see in a river.

"We're trying to do things that you would find in nature, but here we are doing it with boulders and backhoes," Howard said. "It will take a little time."

Crews have also worked on stabilizing the slopes and creating easy access along the slope next to the parking lot for anglers. Because of the parking lot's proximity to U.S. 34, CDOT has also been at the table for discussions, along with the Federal Energy Regulatory Commission, Larimer County and the U.S. Army Corps of Engineers.

It's not known when the site will be open to anglers. The city is likely to let the easement with the Forest Service expire in 2016, but Brieana Reed-Harmel, senior electrical engineer with Loveland Water and Power, said there's still years of work ahead with the Idylwilde Project.

From the former dam to the hydroelectric plant, more than 9,500 feet of pipeline will have to be taken care of, as well as the demolition of the plant at Viestenz-Smith.

Article Comments

We reserve the right to remove any comment that violates our ground rules, is spammy, NSFW, defamatory, rude, reckless to the community, etc.

We expect everyone to be respectful of other commenters. It's fine to have differences of opinion, but there's no need to act like a jerk.

Use your own words (don't copy and paste from elsewhere), be honest and don't pretend to be someone (or something) you're not.

Our commenting section is self-policing, so if you see a comment that violates our ground rules, flag it (mouse over to the far right of the commenter's name until you see the flag symbol and click that), then we'll review it.